Free Exercise clause

"Congress shall make no law ... prohibiting the free exercise" of religion.

This provision has been applied against the states also, thereby prohibiting some types of government interference with the exercise of religion. However, government interference is permitted under some circumstances. For example, In Employment Division v. Smith (1990), the Supreme Court ruled that using illegal drugs in a religious ceremony is illegal.

In recent years conservative majorities on the Supreme Court have used Free Exercise to permit religious activities in public places, such as schools, that liberals want to ban using the Establishment clause. The line is that religious activities sponsored by the government or public schools are not allowed, but religious activities sponsored by private citizens using public facilities are allowed. Furthermore, the government is not allowed to discriminate against religious activities because of their religious content when such activities would otherwise be allowed. That is a student group with religious goals cannot be banned if an identical group with nonreligious goals is not banned.